SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cac0df243d365361667fcd0c43b341c427e4a381e8c39b8e519512cb32c41ac7' 
  AND token = 'tPW3T7lwUzCJPAHXb9geMEGWNyTWNKrNTvDW/j/v2QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}